2/3 x 3/4 x 4/5 x 5/6 x 6/7 x 7/8 x 8/9 x 9/10 x 10/11 x 11/12 x 12/13 x 13/14

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Do this without a calculator.

Notice, all numerators have a matching denominator except 2 in the first term and 14 in the last term.

So we have 2/14

Using 2 as a common factor, we have:
2/2 / 14/2
1/7